Angelica keiskei (Ashitaba in Japanese), a traditional herb in Japan, contains abundant prenylated chalcones. It has been reported that the chalcones from A. keiskei showed such bioactivities as anti-bacterial, anti-cancer and anti-diabetic effects. Xanthoangelol, 4-hydroxyderricin and six new chalcones were isolated in this study from an ethanol extract of A. keiskei by octadecyl silyl (ODS) and silica gel chromatography, and identified by 1D- and 2D-nuclear magnetic resonance (NMR) and high-resolution mass spectrometric analyses. The chalcones from A. keiskei markedly increased the expression of the adiponectin gene and the production of adiponectin in 3T3-L1 adipocytes. These results suggest that the chalcones from A. keiskei might be useful for preventing the metabolic syndrome.